Dynamo electric machines

ABSTRACT

This invention relates to a dynamo electric machine having a rotatable shaft with at least one machine component mounted on the shaft for rotation therewith. The shaft has an axial bore for the passage of a cooling fluid and cooling fluid distributor means mounted on the shaft for discharging cooling fluid on to the component. The cooling fluid distributor means comprises an annular chamber which communicates with the axial bore and with flow control means, the latter ensuring an even or substantially even discharge of fluid therefrom by means of centrifugal force when, in use, the shaft, the component, and the cooling fluid distributor means are rotated.

United States Patent Hunt [ Sept. 5, 1972 [54] DYNAMO ELECTRIC MACHINES[72] inventor: Peter Hunt, Shipley, England [73] Assignee: RotaxLimited, Birmingham,

' England 22 Filed: May 26, 1971 [21] Appl. No.: 147,075

30 Foreign Application Priority Data May 26, 1970 Great Britain..25,308/70- [52] US. Cl ..310/58 [51] Int. Cl. ..H02k 9/00 [58] Fieldof Search ..310/52, 54, 53, 58, 59, 61, 310/64, 59

[56] References Cited 2 I UNITED STATES PATENTS 3,480,810 11/1969 Potter..310/61 3,145,314 8/1964 Becker ..310/64 3,318,253 5/1967 Campolong...310/64 Kudlacik ..310/61 Hauenstein 10/61 Primary Examiner- J. D.Miller Assistant Examiner-R. Skudy Att0rneyHolman & Stern 57 ABSTRACTThis inventionrelates to a dynamo electric machine having a rotatableshaft with at least one machine component mounted on the shaft forrotation therewith. The shaft has an axial bore for the passage of acooling fluidand cooling fluid distributor means mounted on the shaftfor discharging cooling fluid on to the component. The cooling fluiddistributor means comprises an annular chamber which communicates withthe axial bore and with flow control means, the

latter ensuring an even or substantially even discharge of fluidtherefrom by means of centrifugal force when, in use, the shaft, thecomponent, and the cooling fluid distributor means are rotated.

'6 Claims, 3 Drawing Figures PATENTEDSEP 5 m2 3,689 786 SHEET 1 [IF 2FIG];

INVENTOQ M ATTORNEYS PATENTED 1 2 3,689,786

SHEET 2 0F 2 INVENTOR /Z/@/Z ATTORNEYS is mounted on the shaft of themachine.

DYNAMO ELECTRIC MACHINES This invention relates to dynamo electricmachines and more particularly to machines in which rotating componentsare cooled with cooling fluid. The object of the present invention is toprovide a dynamo electric machine having improved means for dischargingcooling fluid onto said rotating components of such a machine.

In accordance with the present invention there is provided a dynamoelectric machine having a rotatable shaft with at least one machinecomponent mounted on the shaft for rotation therewith, the shaft havingan axial bore for the passage of a cooling fluid and cooling fluiddistributor means mounted on said shaft for discharging cooling fluidonto said component, said cooling fluid distributor means comprising anannular chamber which communicates with saidaxial bore and withflowcontrol means, the latter ensuring an even or substantially evendischarge of fluid therefrom by means of centrifugal force when, in use,the shaft, said component, and said cooling fluid distributor means arerotated.

Conveniently, said component may be a rotor winding or a rectifier.

Preferably, said flow control means comprises an annular weirarrangedsothat the free edge of the weir is disposed radially inwardly of aplurality of apertures formed in a wall of said annular chamber andthrough which apertures cooling fluid can in use pass between saidannular chamber and said annular weir, the arrangement being such thatin use an annular reservoir of cooling fluid will be formed behind theweir when the shaft is rotated, said reservoir being in fact filled bymeans of cooling fluid which flows through said aperdischarging from theflow control means passes between the end turns to effect more efficientcooling thereof.

The invention will now be more particularly described with reference tothe accompanying drawings wherein:

FIG. 1 is a partially sectioned view of one embodiment of a dynamoelectric machine according to the present invention,

FIG. 2 shows the end turns of a rotor winding which dynamo electric FIG.3 is 'a fragmentary sectional view illustrating part of the dynamoelectric machine shown in FIG. 1 on an enlarged scale.

Referring now to FIG. 1 of the drawings, there is shown an altemator, byway of example, which includes a stator having stator windings 11.Preferably, the stator is mounted inside a cylinder 12 which lies incontact with the inner surface of a casing 13 of the alternator. Ascroll 14, formed on the inside 2 of the casing 13, is covered by saidcylinder to provide a path for oil or other cooling fluid, which onpassing through said scroll effects cooling of the stator.

A shaft 15 is joumalled for rotation inbearings provided at each end ofthe shaft and the right hand end of the shaft 15 (as viewed in FIG. 1)is adapted to receive a driving device (not shown) for the alternator.

A machine component in the form of a rotor assembly 16 is mounted on theshaft 15 for rotation therewith and windings (only the end turns 17 ofwhich are shown) are mounted on a rotor core 18 so as to provide anumber of poles. The shaft 15 is formed with an axial bore 19 to providea passage for the cooling fluid which is pumped (by means not shown)through a duct 20 formed in the easing, into the scroll 14 and thencethrough a further duct 21 and into the bore l9.v

Cooling fluid distributor means indicated generally by the referencenumeral 22 arealso mounted on the shaft 15 for rotation therewith, saidcooling fluid distributor means being disposed radially inwardly of theend turns 17 of the rotor windings. The cooling fluid distributor means22 comprise a first annular chamber 23 and a second annular chamber 24which have an annular partition 25 disposed therebetween. The firstannular chamber 23 is connected to the bore 19 for communicationtherewith by one relatively large aperture 26 and is connected to thesecond annular chamber 24 for communication therewith by a plurality ofsmaller axially extending apertures 27 provided near the radiallyoutward edge of the partition 25. The second chamber 24 is formed in itsouter peripheral wall 28 with a plurality of openings preferably in theform of axially extending circumferentially spaced slots 29 throughwhich cooling fluid, in use, is discharged. This second chamber isfurther provided with flow control means 30 for ensuring an even orsubstantially even discharge of fluid from the slots 24 in' the outerperipheral wall 28 of the second chamber 24 by means of centrifugalforce when, in use, the shaft 15, the rotor assembly 16 and the coolingfluid distributor means 22 are rotated. The aforesaid flow control means30 comprises a cylindrical tube 31 the outer periphery of which engagesat its end remote from the rotor assembly 16 the interior of the outerperipheral wall of the first chamber 23 and which has a radiallyinwardly extending annular abutment 32 secured to or formed integrallywith the other end thereof, the abutment 32 in effect, forming anannular weir. The latter is so arranged that its free edge is disposedradially inwardly of the apertures 27 formed in the partition 25 so thatin effect an annular reservoir of cooling fluid will be formed behindthe weir when the shaft 15 is rotated, said reservoir being filled bymeans of cooling fluid which is flung out through the aperture 26 andinto the first chamber 23 by centrifugalforce, said cooling fluid thenceflowing through the partition apertures 27 and is then held in positionbehind the weir by centrifugal force. When the reservoir is, in use,full, the cooling fluid will flow I past the weir and will thence bedischarged through the slots 29 in the outer peripheral wall of thesecond I chamber by centrifugal force. The provision of the weir ensuresan even or substantially even discharge of fluid from the aforesaidslots which, by nature of their size, will not become clogged and thisthus reduces the occurrence of possible hot spots (due to unevencooling) on the rotor windings to a minimum. Cooling fluid used incooling the rotor windings falls into a sump (not shown) and may then bepumped away to a heat exchanger.

Conveniently, where said component is in the form of a rotor winding asis the case in the above described embodiment of the invention, then theend tums' 17 of the rotor winding may be axially spaced from each other(as is more clearly shown in FIG. 2) such that cooling fluid dischargingfrom the slots 29 will pass between the end turns thus effecting moreefficient cooling thereof.

In hitherto known arrangements for effecting cooling of componentsmounted on the shaft of a dynamo electric machine either small apertureshave been formed in the wall of the shaft or spraying nipples have beenmounted directly on the shaft or on a sleeve connected to the shaft.However, due to the smaller diameter of apertures through which thefluid has previously been discharged, these apertures have been subjectto clogging, thus resulting in hot spots occurring on components whichare to be cooled.

Although the invention has been described in relation to an alternatorand the cooling of a rotor thereof, it could of course be applied to anyother type of dynamo electric machine in which any component, such as awinding or a rectifying element, is to be cooled by cooling fluid.

Moreover, it is to be understood that the scroll 14 is not essential andit may thus be dispensed with if desired. In this case the ducts 20 and21 may also be dispensed with, cooling fluid entering the axial bore 19through an axially extending passage formed in one end of the alternatorcasing.

In addition, it is also to be understood that if desired the secondannular chamber 24 may also be dispensed with.

I claim:

l A dynamo electric machine having a rotatable shaft, at least onemachine component mounted on the shaft for rotation therewith, an axialborewithin the shaft for the passage of a cooling fluid and coolingfluid distributor means mounted on said shaft for discharging coolingfluid onto said component, said cooling fluid distributor meanscomprising an annular chamber which communicates with said axial boreand flow con-. trol means with which said annular chamber alsocommunicates, said flow control means comprising an annular weirarranged so that the free edge of the weir is disposed radially inwardlyof a plurality of apertures formed in a wall of said annular chamber andthrough which apertures cooling fluid can in use pass between saidannular chamber and said annular weir, the arrangement being such thatin use an annular reservoir of cooling fluid will be formed behind theweir when the shaft is rotated, said reservoir being filled by means ofcooling fluid which flows through said apertures and which is then heldin position behind the weir from which it is subsequently evenlydischarged by means of centrifugal force.

2. A dynamo electric machine as claimed in claim 1 wherein saidcomponent is a rotor winding.

3. A dynamo electric machine as claimed in claim 1 wherein said annularweir is disposed within a further annular chamber which is formed in itsouter wall with a plurality of openings through which cooling fluidwill, in use be discharged, said apertured wall forming a partitionbetween the two annular chambers.

5. A dynamo electric machine as claimed in claim 4 wherein said openingsformed in the peripheral wall of said further chamber are in the form ofaxially extending circumferentially spaced slots.

6. A dynamo electric machine as claimed in claim 2 wherein the end turnsof said winding are axially spaced from each other,-the arrangementbeing such that fluid discharging from the flow control means passesbetween the end turns to effect more efficient cooling thereof.

1. A dynamo electric machine having a rotatable shaft, at least onemachine component mounted on the shaft for rotation therewith, an axialbore within the shaft for the passage of a cooling fluid and coolingfluid distributor means mounted on said shaft for discharging coolingfluid onto said component, said cooling fluid distributor meanscomprising an annular chamber which communicates with said axial boreand flow control means with which said annular chamber alsocommunicates, said flow control means comprising an annular weirarranged so that the free edge of the weir is disposed radially inwardlyof a plurality of apertures formed in a wall of said annular chamber andthrough which apertures cooling fluid can in use pass between saidannular chamber and said annular weir, the arrangement being such thatin use an annular reservoir of cooling fluid will be formed behind theweir when the shaft is rotated, said reservoir being filled by means ofcooling fluid which flows through said apertures and which is then heldin position behind the weir from which it is subsequently evenlydischarged by means of centrifugal force.
 2. A dynamo electric machineas claimed in claim 1 wherein said component is a rotor winding.
 3. Adynamo electric machine as claimed in claim 1 wherein said component isa rectifier.
 4. A dynamo electric machine as claimed in claim 1 whereinsaid annular weir is disposed within a further annular chamber which isformed in its outer wall with a plurality of openings through whichcooling fluid will, in use be discharged, said apertured wall forming apartition between the two annular chambers.
 5. A dynamo electric machineas claimed in claim 4 wherein said openings formed in the peripheralwall of said further chamber are in the form of axially extendingcircumferentially spaced slots.
 6. A dynamo electric machine as claimedin claim 2 wherein the end turns of said winding are axially spaced fromeach other, the arrangement being such that fluid discharging from theflow control means passes between the end turns to effect more efficientcooling thereof.